Methods for filling a gap feature on a substrate surface and related semiconductor structures

ABSTRACT

A method for filling a gap feature on a substrate surface is disclosed. The method may include: providing a substrate comprising a non-planar surface including one or more gap features; depositing a metal oxide film over a surface of the one or more gap features by a cyclical deposition process; contacting the metal oxide with an organic ligand vapor; and converting at least a portion of the metal oxide film to a porous material thereby filling the one or more gap features. Semiconductor structures including a metal-organic framework material formed by the methods of the disclosure are also disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent ApplicationSer. No. 62/950,904 filed Dec. 19, 2019 titled “METHODS FOR FILLING AGAP FEATURE ON A SUBSTRATE SURFACE AND RELATED SEMICONDUCTORSTRUCTURES,” the disclosure of which is hereby incorporated by referencein its entirety.

PARTIES OF JOINT RESEARCH AGREEMENT

The invention claimed herein was made by, or on behalf of, and/or inconnection with a joint research agreement between University ofHelsinki and ASM Microchemistry Oy. The agreement was in effect on andbefore the date the claimed invention was made, and the claimedinvention was made as a result of activities undertaken within the scopeof the agreement.

FIELD OF INVENTION

The present disclosure relates generally to methods for filling a gapfeature on a substrate and particularly to methods for depositing ametal oxide film by a cyclical deposition process and subsequentlyconverting the metal oxide film to a porous film, thereby filling one ormore gap features. The present disclosure is also related generally tosemiconductor structures comprising a metal-organic framework materialdisposed in and filling one or more gap features.

BACKGROUND OF THE DISCLOSURE

Semiconductor fabrication processes for forming semiconductor devicestructures, such as, for example, transistors, memory elements, andintegrated circuits, are wide ranging and may include depositionprocesses, etch processes, thermal annealing processes, lithographyprocesses, and doping processes, amongst others.

A particular semiconductor fabrication process commonly utilized is thedeposition of a dielectric film into a gap feature thereby filling thegap feature with the dielectric material, a process commonly referred toas “gap fill”. Semiconductor substrates may comprise a multitude of gapfeatures on a substrate with a non-planar surface, the gap featuresbeing disposed between protruding portions of the substrate surface orindentations formed in a substrate surface. As semiconductor devicestructure geometries have decreased and high aspect ratio features havebecome more common place in such semiconductor device structure as DRAM,flash memory, and logic, it has become increasingly difficult to fillthe multitude of gap features with a material having the desiredcharacteristics.

Deposition methods such as high density plasma (HDP), sub-atmosphericchemical vapor deposition (SACVD), and low pressure chemical vapordeposition (LPCVD) have been used for gap fill processes, but theseprocesses commonly do not achieve the desired gap fill capability.Flowable chemical vapor deposition and spin-on dielectric (SOD) methodscan achieve the desired gap fill, but these methods are especiallycomplex and costly to integrate, as they may require additionalprocessing steps. Atomic layer deposition (ALD) processes have also beenused for gap fill, but these processes may suffer from long processingtimes and low throughput, especially for large gaps. In some cases,multi-step deposition processes are used, includingdeposition-etch-deposition processes, which require a distinct etchingoperation between subsequent deposition operations. Whiledeposition-etch-deposition processes may be useful for gap fillprocesses, it would be preferable to use a process, which does notinvolve an etch step. Accordingly, methods and associated semiconductorstructures are desired for filling gap features on a non-planarsubstrate with a gap fill material with improved characteristics andwith a simplified fabrication process.

SUMMARY OF THE DISCLOSURE

This summary is provided to introduce a selection of concepts in asimplified form. These concepts are described in further detail in thedetailed description of example embodiments of the disclosure below.This summary is not intended to identify key features or essentialfeatures of the claimed subject matter, nor is it intended to be used tolimit the scope of the claimed subject matter.

In some embodiments, methods for filling a gap feature on a substratesurface are provided. The method may comprise: providing a substratecomprising a non-planar surface including one or more gap features;depositing a metal oxide film over a surface of the one or more gapfeatures by a cyclical deposition process; contacting the metal oxidefilm with an organic ligand vapor; and converting at least a portion ofthe metal oxide film to a porous material thereby filling the one ofmore gap features.

In some embodiments, semiconductor structures are provided. Thesemiconductor structure may comprise: a substrate comprising anon-planar surface including one or more gap features; and ametal-organic framework material disposed in and filling the one or moregap features.

For purposes of summarizing the invention and the advantages achievedover the prior art, certain objects and advantages of the invention havebeen described herein above. Of course, it is to be understood that notnecessarily all such objects or advantages may be achieved in accordancewith any particular embodiment of the invention. Thus, for example,those skilled in the art will recognize that the invention may beembodied or carried out in a manner that achieves or optimizes oneadvantage or group of advantages as taught or suggested herein withoutnecessarily achieving other objects or advantages as may be taught orsuggested herein.

All of these embodiments are intended to be within the scope of theinvention herein disclosed. These and other embodiments will becomereadily apparent to those skilled in the art from the following detaileddescription of certain embodiments having reference to the attachedfigures, the invention not being limited to any particular embodiment(s)disclosed.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

While the specification concludes with claims particularly pointing outand distinctly claiming what are regarded as embodiments of theinvention, the advantages of embodiments of the disclosure may be morereadily ascertained from the description of certain examples of theembodiments of the disclosure when read in conjunction with theaccompanying drawings, in which:

FIG. 1 illustrates a non-limiting exemplary process flow for filling agap feature according to the embodiments of the disclosure;

FIG. 2 illustrates a non-limiting exemplary process representing acyclical deposition process utilized as a sub-process in the process forfilling a gap feature according to the embodiments of the disclosure;

FIGS. 3A-3C illustrate cross-sectional schematic views of semiconductorstructures formed by the gap fill processes according to the embodimentsof the disclosure;

FIGS. 4A-4E illustrate additional cross-sectional schematic views ofsemiconductor structures formed by the gap fill processes according tothe embodiments of the disclosure;

FIG. 5 illustrates a field emission scanning electron microscope (FESEM)image of a semiconductor structure including a gap feature with aconformal metal oxide disposed thereon according to the embodiments ofthe disclosure;

FIG. 6 illustrates a cross-sectional view of a semiconductor structureincluding a gap feature filled with a dielectric gap fill materialincluding a seam as formed by prior art methods;

FIG. 7 illustrates a scanning transmission electron microscope (STEM)image of a semiconductor structure including a number of gap featuresfilled with a porous material according to the embodiments of thedisclosure; and

FIG. 8 illustrates an x-ray diffraction (XRD) measurement taken from aporous gap fill material according to the embodiments of the disclosure.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Although certain embodiments and examples are disclosed below, it willbe understood by those in the art that the invention extends beyond thespecifically disclosed embodiments and/or uses of the invention andobvious modifications and equivalents thereof. Thus, it is intended thatthe scope of the invention disclosed should not be limited by theparticular disclosed embodiments described below.

The illustrations presented herein are not meant to be actual views ofany particular material, structure, or device, but are merely idealizedrepresentations that are used to describe embodiments of the disclosure.

As used herein, the term “cyclic deposition” may refer to the sequentialintroduction of precursors (reactants) into a reaction chamber todeposit a film over a substrate and includes deposition techniques suchas atomic layer deposition and cyclical chemical vapor deposition.

As used herein, the term “cyclical chemical vapor deposition” may referto any process wherein a substrate is sequentially exposed to two ormore volatile precursors, which react and/or decompose on a substrate toproduce a desired deposition.

As used herein, the term “substrate” may refer to any underlyingmaterial or materials that may be used, or upon which, a device, acircuit, or a film may be formed.

As used herein, the term “atomic layer deposition” (ALD) may refer to avapor deposition process in which deposition cycles, preferably aplurality of consecutive deposition cycles, are conducted in a reactionchamber. Typically, during each cycle the precursor is chemisorbed to adeposition surface (e.g., a substrate surface or a previously depositedunderlying surface such as material from a previous ALD cycle), forminga monolayer or sub-monolayer that does not readily react with additionalprecursor (i.e., a self-limiting reaction). Thereafter, if necessary, areactant (e.g., another precursor or reaction gas) may subsequently beintroduced into the process chamber for use in converting thechemisorbed precursor to the desired material on the deposition surface.Typically, this reactant is capable of further reaction with theprecursor. Further, purging steps may also be utilized during each cycleto remove excess precursor from the process chamber and/or remove excessreactant and/or reaction byproducts from the process chamber afterconversion of the chemisorbed precursor. Further, the term “atomic layerdeposition,” as used herein, is also meant to include processesdesignated by related terms such as, “chemical vapor atomic layerdeposition”, “atomic layer epitaxy” (ALE), molecular beam epitaxy (MBE),gas source MBE, or organometallic MBE, and chemical beam epitaxy whenperformed with alternating pulses of precursor composition(s), reactivegas, and purge (e.g., inert carrier) gas.

As used herein, the term “film” may refer to any continuous ornon-continuous structures, material, or materials, deposited by themethods disclosed herein. For example, a “film” could include 2Dmaterials, nanorods, nanotubes, nanolaminates, or nanoparticles or evenpartial or full molecular layers or partial or full atomic layers orclusters of atoms and/or molecules.

As used herein, the term “gap feature” may refer to an opening or cavitydisposed between one or more inclined surfaces of a non-planar surface.The term “gap feature” may refer to an opening or cavity disposedbetween opposing inclined sidewall(s) of two protrusions extendingvertically from the surface of the substrate. The term “gap feature” mayrefer to an opening or cavity disposed between one or more opposinginclined sidewalls of an indentation extending vertically into thesurface of the substrate.

As used herein, the term “metal oxide” may refer to a material includingboth a metal component and an oxygen component.

As used herein, the term “organic vapor ligand” may refer to a vaporphase organic molecule or ion which may bind to a metal species to forma coordination complex.

As used herein, the term “porous material” may refer to a materialcomprising a plurality of voids.

As used herein, the term “metal-organic framework” may refer to a porousmaterial comprising metal ions or clusters of metal ions coordinated toorganic ligands with more than one coordination group. For simplicityreasons herein the term “metal-organic framework” (MOF) also coverscoordination polymers manufactured by the methods described herein,which can be amorphous and/or non-porous materials, where typically“metal-organic framework” is considered to be a crystalline material. Acoordination polymer may be an inorganic or organometallic structurecomprising polymer(s) and also containing metal cation centers linked byligands. The coordination polymer can be considered to be a coordinationcompound with repeating coordination entities extending in 1, 2, or 3dimensions. A coordination polymer can also be described as a polymerwhose repeat units comprises coordination complexes. As stated here inthe embodiments where MOFs are described, it also comprises coordinationpolymers.

As used herein, the term “seam” may refer to a line or one or more voidsformed by the abutment of edges formed in a gap fill material, and the“seam” can be confirmed using a scanning transmission electronmicroscopy (STEM) or transmission electron microscopy (TEM) wherein ifobservations reveals a clear vertical line or one or more vertical voidsin the gap fill material feature, a “seam” is present.

As used herein, the term “seamless” may refer to gap fill materialdisposed in a gap, trench or via or other three-dimensional featurewhich has no seam.

As used herein, the term “pin-hole” may refer to a cavity which extendsthrough the thickness of a material, and “pin-hole free” may refer to amaterial which has no pin-holes.

A number of example materials are given throughout the embodiments ofthe current disclosure, it should be noted that the chemical formulasgiven for each of the example materials should not be construed aslimiting and that the non-limiting example materials given should not belimited by a given example stoichiometry.

The present disclosure includes methods that may be employed for thefilling of one or more gap features disposed on or in a non-planarsurface of a substrate. The gap filling process may comprise depositinga metal oxide film over the non-planar surface of the substrate by acyclical deposition process and subsequently converting the metal oxidefilm to a porous material by contacting the metal oxide film with anorganic ligand vapor thereby converting at least a portion of the metaloxide film to a porous material. The porous material may have a lowermolar density or lower volumetric mass density than the metal oxide filmand therefore as the metal oxide is converted to the porous material anexpansion of the film may take place, the expansion resulting in aporous film which fills the one or more gap features without the needfor additional deposition processes.

The filling of one or more gap features, such as, for example, one ormore trenches, is an important semiconductor fabrication process.Therefore novel, efficient, and cost effective gap fill processes arehighly desirable. The current disclosure comprises embodiments wherein ametal oxide film may be deposited and subsequently at least partiallyconverted to a porous material, thereby filling the one or more gapfeatures. The porous material may comprise metal-organic framework (MOF)materials, which are a class of hybrid organic-inorganic crystallineporous materials comprising metal ions or clusters of metal ionsconnected by multi-topic organic linkers in a way such that pores areformed in the crystal structure. The material characteristics of MOFmaterials may be adjustable depending on a number of factors including,but not limited to, the composition of the metal oxide film, the choiceof organic ligand vapor, and the parameters of the conversion process.As a non-limiting example, the size of the pores in the porous materialmay be adjustable permitting the tunability of the dielectric constantof the porous material. In addition, the MOF materials may be furthermodified by functionalization of the internal surfaces of the porousmaterial.

Therefore, the embodiments of the disclosure may include methods forfilling a gap feature on a substrate surface. In some embodiments, themethods may comprise: providing a substrate comprising a non-planarsurface including one or more gap features; depositing a metal oxidefilm over a surface of the one or more gap features by a cyclicaldeposition process; contacting the metal oxide film with an organicligand; and converting at least a portion of the metal oxide film to aporous material thereby filling the one or more gap features.

The embodiments of the disclosure may be described in greater detailwith reference to FIG. 1 which illustrates a non-limiting exemplaryprocess flow 100 for filling one or more gap features, FIG. 2 whichillustrates a non-limiting exemplary process representing a cyclicaldeposition process 120 utilized as a sub-process in the process forfiling a gap feature, FIGS. 3A-3C which illustrate cross-sectionalschematic views of semiconductor structures formed by the gap fillprocesses described herein, and FIGS. 4A-4E, which illustratecross-sectional schematic views of additional semiconductor structuresformed by the gap fill processes described herein.

In more detail, exemplary gap fill process 100 (FIG. 1) may commence bymeans of a process 110 which comprises, providing a substrate comprisinga non-planar surface including one or more gap features.

In some embodiments of the disclosure, the substrate, such as substrate302 of FIG. 3A, may comprise one or more materials including, but notlimited to, silicon (Si), germanium (Ge), germanium tin (GeSn), silicongermanium (SiGe), silicon germanium tin (SiGeSn), silicon carbide (SiC),or a group III-V semiconductor material, such as, for example, galliumarsenide (GaAs), gallium phosphide (GaP), or gallium nitride (GaN). Insome embodiments of the disclosure, the substrate 302 may comprise anengineered substrate wherein a surface semiconductor layer is disposedover a bulk support with an intervening buried oxide (BOX) disposedthere between.

In some embodiments, the substrate 302 may include semiconductor devicestructures formed into or onto a surface of the substrate, for example,a substrate may comprise partially fabricated semiconductor devicestructures, such as, for example, transistors and/or memory elements. Insome embodiments, the substrate may contain monocrystalline surfacesand/or one or more secondary surfaces that may comprise anon-monocrystalline surface, such as a polycrystalline surface and/or anamorphous surface. Monocrystalline surfaces may comprise, for example,one or more of silicon (Si), silicon germanium (SiGe), germanium tin(GeSn), or germanium (Ge). Polycrystalline or amorphous surfaces mayinclude dielectric materials, such as oxides, oxynitrides or nitrides,such as, for example, silicon oxides and silicon nitrides.

In some embodiments of the disclosure, the substrate 302 may comprise anon-planar surface, such as an upper exposed surface, including one ormore gap features 304.

In some embodiments, the substrate 302 may comprise a plurality ofprotrusions and in such embodiments a gap feature 304 may comprise theopening or cavity disposed between opposing inclined sidewalls 306A and306B of two adjacent protrusions extending vertically from the surfaceof the substrate 3002. In some embodiments, the plurality of protrusionsmay comprise the same material as the substrate 302, whereas inalternative embodiments, the plurality of protrusions may comprise adifferent material to the substrate 302.

In some embodiments, the substrate 302 may comprise a plurality ofindentations and in such embodiments a gap feature 304 may comprise anopening or cavity disposed between inclined sidewalls 306A and 306B ofan indentation extending vertically into the surface of substrate 302.

In some embodiments of the disclosure, the one or more gap features 304may have a maximum aspect ratio (height: width) of greater than 2:1, orgreater than 5:1, or greater than 10:1, or greater than 25:1, or evengreater than 50:1. In some embodiments, the one or more gap features 304may have a minimum aspect ratio of less than 50:1, or less than 25:1, orless than 10:1, or less than 5:1, or less than 2:1, or even less than1:1.

The exemplary gap fill process 100 may continue by means of a processblock 120 comprising, depositing a metal oxide film over a surface ofthe one or more gap features by a cyclical deposition process.

A non-limiting example embodiment of a cyclical deposition process mayinclude atomic layer deposition (ALD), wherein ALD is based on typicallyself-limiting reactions, whereby sequential and alternating pulses ofreactants are used to deposit about one atomic (or molecular) monolayerof material per deposition cycle. The deposition conditions andprecursors are typically selected to provide self-saturating reactions,such that an absorbed layer of one reactant leaves a surface terminationthat is non-reactive with the gas phase reactants of the same reactants.The substrate is subsequently contacted with a different precursor thatreacts with the previous termination to enable continued deposition.Thus, each cycle of alternated pulses typically leaves no more thanabout one monolayer of the desired material. However, as mentionedabove, the skilled artisan will recognize that in one or more ALD cyclesmore than one monolayer of material may be deposited, for example, ifsome gas phase reactions occur despite the alternating nature of theprocess.

A cyclical deposition process for depositing a metal oxide film maycomprise at least one unit cycle, wherein one unit cycle may comprise,exposing the substrate to a first precursor, removing any unreactedfirst precursor and reaction byproducts from the reaction chamber, andexposing the substrate to a second precursor, followed by a secondremoval step. In some embodiments, the first precursor of the cyclicaldeposition cycle may comprise a metal vapor phase precursor (“the metalprecursor”) and second precursor of the cyclical deposition cycle maycomprise an oxidizing precursor (“the oxidizing precursor”).

Precursors may be separated by inert gases, such as argon (Ar) ornitrogen (N₂), to prevent gas-phase reactions between precursors andenable self-saturating surface reactions. In some embodiments, however,the substrate may be moved to separately contact a first precursor and asecond precursor. Because the reactions self-saturate, stricttemperature control of the substrates and precise dosage control of theprecursors may not be required. However, the substrate temperature ispreferably such that an incident gas species does not condense intomonolayers nor decompose on the surface. Surplus chemicals and reactionbyproducts, if any, are removed from the substrate surface, such as bypurging the reaction space or by moving the substrate, before thesubstrate is contacted with the next reactive chemical. Undesiredgaseous molecules can be effectively expelled from a reaction space withthe help of an inert purging gas. A vacuum pump may be used to assist inthe purging.

Reactors capable of being used to deposit metal oxide films can be usedfor the deposition processes described herein. Such reactors include ALDreactors, as well as CVD reactors, configured to provide the precursors.According to some embodiments, a showerhead reactor may be used.According to some embodiments, cross-flow, batch, minibatch, or spatialALD reactors may be used.

In some embodiments of the disclosure, a batch reactor may be used. Insome embodiments, a vertical batch reactor may be utilized. In otherembodiments, the batch reactor comprises a minibatch reactor configuredto accommodate 10 or fewer wafers, 8 or fewer wafers, 6 or fewer wafers,4 or fewer wafers, or 2 or fewer wafers. In some embodiments in which abatch reactor is used, wafer-to-wafer non-uniformity is less than 3% (1sigma), less than 2%, less than 1%, or even less than 0.5%.

The cyclical deposition processes and particularly the gap fillprocesses described herein may optionally be carried out in a reactor orreaction chamber connected to a cluster tool. In a cluster tool, becauseeach reaction chamber is dedicated to one type of process, thetemperature of the reaction chamber in each module can be kept constant,which improves the throughput compared to a reactor in which thesubstrate is heated up to the process temperature before each run.Additionally, in a cluster tool it is possible to reduce the time topump the reaction chamber to the desired process pressure levels betweensubstrates. In some embodiments of the disclosure, the depositionprocess may be performed in a cluster tool comprising multiple reactionchambers, wherein each individual reaction chamber may be utilized toexpose the substrate to an individual precursor gas and the substratemay be transferred between different reaction chambers for exposure tomultiple precursors gases, the transfer of the substrate being performedunder a controlled ambient to prevent oxidation/contamination of thesubstrate. For example, a first reaction chamber may be configured forperformed a cyclical deposition process for depositing a metal oxidefilm and second reaction chamber may be configured for subsequentlycontacting the metal oxide film with an organic ligand vapor.

A stand-alone reactor may be equipped with a load-lock. In that case, itis not necessary to cool down the reaction chamber between each run. Insome embodiments, a deposition process for depositing a metal oxidefilm, such as a zinc oxide film, may comprise a plurality of depositioncycles, i.e., a plurality of unit cycles, for example ALD cycles orcyclical CVD cycles.

In some embodiments, a cyclical deposition process may be used todeposit the metal oxide film of the current disclosed on a non-planarsubstrate and the cyclical deposition process may comprise one or moreALD type process. In some embodiments, a cyclical deposition process maycomprise a hybrid ALD/CVD or a cyclical CVD process. For example, insome embodiments, the growth rate of an ALD process may be low comparedwith a CVD process. One approach to increase the growth rate may be thatof operating at a higher substrate temperature than that typicallyemployed in an ALD process, resulting in at least a portion of thedeposition being provided by a chemical vapor deposition type process,but still taking advantage of the sequential introduction of precursors,such a process may be referred to as cyclical CVD.

In some embodiments of the disclosure, a cyclical deposition process maybe utilized to deposit a metal oxide film comprising a metal componentand an oxygen component, and a non-limiting example of such a cyclicaldeposition process may be understood with reference to FIG. 2, whichillustrates exemplary cyclical deposition process 120 for depositing ametal oxide film, the cyclical deposition process 120 being asub-process of the exemplary gap fill process 100 (FIG. 1).

In more detail, exemplary cyclical deposition process 120 may commenceby providing the substrate with a non-planar surface into a reactionchamber and heating the substrate to a desired deposition temperature.

The reaction chamber utilized for the deposition may be an atomic layerdeposition reaction chamber, or a chemical vapor deposition reactionchamber, or any of the reaction chambers as previously described herein.In some embodiments of the disclosure, the substrate may be heated to adesired deposition temperature during the cyclical deposition process.For example, the substrate may be heated to a substrate temperature ofless than approximately 750° C., or less than approximately 650° C., orless than approximately 550° C., or less than approximately 450° C., orless than approximately 350° C., or less than approximately 250° C., oreven less than approximately 150° C. In some embodiments of thedisclosure, the substrate temperature during the cyclical depositionprocess may be between 300° C. and 750° C., or between 400° C. and 600°C., or between 400° C. and 450° C. Upon heating the substrate to adesired deposition temperature, the exemplary cyclical depositionprocess 120 may continue by means of a process block 122, whichcomprises contacting the substrate with a metal vapor phase precursor.In some embodiments of the disclosure, the metal vapor phase precursormay comprise a metal selected from the group comprising zinc (Zn),zirconium (Zr), aluminum (Al), copper (Cu), or iron (Fe). In someembodiments, the metal vapor phase reactant may comprise a metal halidevapor phase precursor, such as, for example, a metal chloride vaporphase precursor, a metal iodide vapor phase precursor, or a metalbromide vapor phase precursor. In some embodiments the metal vapor phasereactant may comprise a metal halide vapor phase precursor, such asZrCl₄, ZnCl₂, AlCl₃, CuCl or FeCl₃.

In some embodiments, the metal vapor phase precursor may comprise ametalorganic vapor phase precursor. In some embodiments, themetalorganic vapor phase precursor may comprise a metalorganic ororganometallic zinc precursor, i.e., a metalorganic precursor comprisinga zinc element. In some embodiments, the metalorganic zinc precursor maycomprise at least one of dimethylzinc (ZnMe₂), diethylzinc (ZnEt₂),methylzinc isopropoxide (ZnMe(OPr)), or zinc acetate (Zn(CH₃CO₂)₂).

In some embodiments the metalorganic vapor phase precursor is selectedfrom one or more of the group consisting of (MeCp)₂Zr(OMe)₂,(MeCp)₂Zr(OMe)Me, tetrakis(ethylmethyl)aminozirconium (TEMAZr),tetrakis(dimethyl)aminozirconium (TDMAZr),tetrakis(diethyl)aminozirconium (TDEAZr) ortris(dimethylamino)cyclopentadienylzirconium or derivatives thereof.

In some embodiments the metalorganic vapor phase precursor may comprisea metalorganic or organometallic aluminum precursors. In someembodiments the metalorganic vapor phase precursor is selected from oneor more of the group consisting of trimethylaluminum (TMA),triethylaluminum (TEA), dimethylaluminum hydride (DMAH),dimethylaluminum isopropoxide (DMAI), dimethylethylaminealane (DMEAA),trimethylaminealane (TEAA), N-methylpyrroridinealane (MPA),tri-isopropoxide aluminum, tri-isobutylaluminum (TIBA), andtritertbutylaluminum (TTBA). In some embodiments, the metalorganic vaporphase precursor is not trimethylaluminum (TMA).

In some embodiments the metalorganic vapor phase precursor may comprisea metalorganic or organometallic copper precursors. In some embodimentsthe copper precursors is selected from, copper amidinates,bis(acetylacetonate)copper(II) andbis(2,2,6,6-tetramethyl-3,5-heptanedionato)copper(II) and derivatives ofthose.

In some embodiments the copper precursors is selected from copperbetadiketonate compounds, copper betadiketiminato compounds, copperaminoalkoxide compounds, such as Cu(dmae)₂, Cu(deap)₂ or Cu(dmamb)₂,copper amidinate compounds, such as Cu(^(s)Bu-amd)₂, coppercyclopentadienyl compounds, copper carbonyl compounds and combinationsthereof. In some embodiments, Cu(acac)₂ Cu(hfac)₂ or Cu(thd)₂ compoundsare used, where thd is 2,2,6,6-tetramethyl-3,5-heptanedionato.Cu(acac)L, Cu(hfac)L Cu(thd)L adduct compounds where L is a neutraladduct ligand. In some embodiments the non-halide containing copperprecursor is copper(II)acetate, [Cu(HIVIDS)]₄ or Cu(nhc)HMDS(1,3-di-isopropyl-imidazolin-2-ylidene copper hexamethyl disilazide) orCu-betadiketiminates, such as Cu(dki)VTMS (dki=diketiminate).

In some embodiments the metalorganic vapor phase precursor may comprisea metalorganic or organometallic iron precursors. In some embodiments ofthe disclosure, the metalorganic or organometallic iron precursor maycomprise a metalorganic iron precursor, i.e., a metalorganic precursorcomprising an iron element. In some embodiments, the metalorganic ironprecursor may comprise cyclopentadienyl compounds of iron, ironbetadiketonate compounds, iron alkylamine or iron amidinate compounds orother metalorganic iron compounds. In some embodiments, the metalorganiciron precursor may be selected from the group consisting ofbis(N,N′-di-tertbutylacetamidinato)iron(II),biscyclopentadienyl)iron(II), or cyclohexadienetricarbonyliron(0).

In some embodiments of the disclosure, contacting the substrate with ametal vapor phase precursor may comprise pulsing the metal precursorinto the reaction chamber and subsequently contacting the substrate tothe metal precursor for a time period of between about 0.01 seconds andabout 60 seconds, between about 0.05 seconds and about 10 seconds, orbetween about 0.1 seconds and about 5.0 seconds. In addition, during thepulsing of the metal precursor, the flow rate of the metal precursor maybe less than 2000 sccm, or less than 500 sccm, or even less than 100sccm. In addition, during the pulsing of the metal precursor over thesubstrate the flow rate of the metal precursor may range from about 1 to2000 sccm, from about 5 to 1000 sccm, or from about 10 to about 500sccm.

The exemplary cyclic deposition cycle 120 of FIG. 2 may continue bypurging the reaction chamber. For example, excess metal vapor phaseprecursor and reaction byproducts (if any) may be removed from thesurface of the substrate, e.g., by pumping with an inert gas. In someembodiments of the disclosure, the purge process may comprise a purgecycle wherein the substrate surface is purged for a time period of lessthan approximately 5.0 seconds, or less than approximately 3.0 seconds,or even less than approximately 2.0 seconds. Excess metal vapor phaseprecursor and any possible reaction byproducts may be removed with theaid of a vacuum, generated by a pumping system in fluid communicationwith the reaction chamber.

Upon purging the reaction chamber with a purge cycle the exemplarycyclical deposition process 120 may continue with a process block 124comprising, contacting the substrate with an oxidizing precursor. Insome embodiments the oxidizing precursor comprises at least one of water(H₂O), hydrogen peroxide (H₂O₂), ozone (O₃), or oxides of nitrogen, suchas, for example, nitrogen monoxide (NO), nitrous oxide (N₂O), ornitrogen dioxide (NO₂). In some embodiments of the disclosure, theoxygen precursor may comprise an organic alcohol, such as, for example,isopropyl alcohol. In some embodiments of the disclosure, the oxidizingprecursor may comprise an oxygen based plasma, i.e., a plasma generatedfrom an oxygen containing gas, such as, for example, molecular oxygen(O₂), or ozone (O₃), wherein the oxygen based plasma may comprise oxygenatoms (O), oxygen ions, oxygen radicals, and oxygen excited species.

In some embodiments of the disclosure, contacting the substrate with anoxidizing precursor may comprise pulsing the oxidizing precursor intothe reaction chamber and subsequently contacting the substrate to theoxidizing precursor for a time period of between about 0.01 seconds andabout 60 seconds, between about 0.05 seconds and about 10 seconds, orbetween about 0.1 seconds and about 5.0 seconds. In addition, during thepulsing of the oxidizing precursor, the flow rate of the oxidizingprecursor may be less than 2000 sccm, or less than 500 sccm, or evenless than 100 sccm. In addition, during the pulsing of the oxidizingprecursor over the substrate the flow rate of the oxidizing precursormay range from about 1 to 2000 sccm, from about 5 to 1000 sccm, or fromabout 10 to about 500 sccm.

The exemplary cyclical deposition cycle 120 of FIG. 2 may continue bypurging the reaction chamber. For example, excess oxidizing precursorand reaction byproducts (if any) may be removed from the surface of thesubstrate, e.g., by pumping with an inert gas. In some embodiments ofthe disclosure, the purge process may comprise a purge cycle wherein thesubstrate surface is purged for a time period of less than approximately5.0 seconds, or less than approximately 3.0 seconds, or even less thanapproximately 2.0 seconds. Excess oxidizing precursor and any possiblereaction byproducts may be removed with the aid of a vacuum, generatedby a pumping system in fluid communication with the reaction chamber.

The cyclical deposition process 120 of FIG. 2 may continue by means of aprocess block 126 which comprises a decision gate, the decision gatebeing dependent on the thickness of the metal oxide film to be depositedby the exemplary cyclical deposition process 120. If the metal oxidefilm deposited is at an insufficient thickness for subsequent processsteps then the cyclical deposition process 120 may return to the processblock 122 and the substrate may be contacted with the metal vapor phaseprecursor (process block 122) and contacted with the oxidizing precursor(process block 124). For example, a single deposition cycle, i.e. a unitcycle, of the cyclical deposition process 120 may comprise: contactingthe substrate with the metal vapor phase precursor, purging the reactionchamber, contacting the substrate with the oxidizing precursor, andpurging the reaction chamber again. To deposit a metal oxide film to adesired thickness the cyclical deposition process 120 may be repeatedone or more times until a desired thickness of a metal oxide film isdeposited, at which point the exemplary cyclical deposition process 120may exit via a process block 128.

It should be appreciated that in some embodiments of the disclosure, theorder of contacting of the substrate with the metal vapor phaseprecursor and the oxidizing precursor may be such that the substrate isfirst contacted with the oxidizing precursor followed by the metalprecursor. In addition, in some embodiments, the cyclical depositionprocess 120 may comprise, contacting the substrate with the metalprecursor one or more times prior to contacting the substrate with theoxidizing precursor one or more times. In some embodiments, the cyclicaldeposition process 120 may comprise, contacting the substrate with theoxidizing precursor one or more times prior to contacting the substratewith the metal precursor one or more times.

In some embodiments of the disclosure, the exemplary cyclical depositionprocess 120 alternatingly contacts the substrate with a metal precursorand an oxidizing precursor and the reaction between the metal precursorand the oxygen precursor may deposit a metal oxide film over a surfaceof the substrate. In some embodiments of the disclosure, the metal oxidefilm may comprise at least one of a zinc oxide, a zirconium oxide, analuminum oxide, a copper oxide, or an iron oxide. In particularembodiments, the metal oxide film deposited by the cyclical depositionprocess 120 may comprise a zinc oxide.

The metal oxide films deposited by the cyclical deposition processdisclosed herein, such as, for example, a zinc oxide, may be acontinuous film. In some embodiments, the metal oxide film may becontinuous at a thickness below approximately 100 nanometers, or belowapproximately 60 nanometers, or below approximately 50 nanometers, orbelow approximately 40 nanometers, or below approximately 30 nanometers,or below approximately 20 nanometers, or below approximately 10nanometers, or even below approximately 5 nanometers. The continuityreferred to herein can be physical continuity or electrical continuity.In some embodiments of the disclosure the thickness at which the metaloxide film may be physically continuous may not be the same as thethickness at which the metal oxide film is electrically continuous, andvice versa.

In some embodiments of the disclosure, the metal oxide film depositedaccording to the cyclical deposition processes described herein, e.g., azinc oxide, aluminum oxide, zirconium oxide film, copper oxide and ironoxide may have a thickness from about 20 nanometers to about 100nanometers, or about 20 nanometers to about 60 nanometers. In someembodiments, a metal oxide film deposited according to some of theembodiments described herein may have a thickness greater than about 20nanometers, or greater than about 30 nanometers, or greater than about40 nanometers, or greater than about 50 nanometers, or greater thanabout 60 nanometers, or greater than about 100 nanometers, or greaterthan about 250 nanometers, or greater than about 500 nanometers, orgreater. In some embodiments a metal oxide film deposited according tosome of the embodiments described herein may have a thickness of lessthan about 50 nanometers, or less than about 30 nanometers, or less thanabout 20 nanometers, or less than about 15 nanometers, or less thanabout 10 nanometers, or less than about 5 nanometers, or less than about3 nanometers, or less than about 2 nanometers, or even less than about 1nanometer.

In some embodiments of the disclosure, the metal oxide film may bedeposited on a substrate comprising one or more gap features, asillustrated in FIG. 3B. In more detail, the metal oxide film 306 may bedisposed over a surface of the more gap features 304 disposed in or onsubstrate 302. In some embodiments, the metal oxide film 306 maydeposited in a conformal manner over the one or more gap features 304,wherein the term “conformal” denotes a metal oxide film 306 having athickness that does not deviate from greater than 30%, or greater than20%, or even greater than 10%, of an average value for the thickness ofthe metal oxide film 306. In some embodiments, the metal oxide film 306may be deposited over the one or more gap features 304, i.e., highaspect ratio features, with a step coverage greater than approximately90%, or greater than approximately 95%, or greater than approximately99%, or even substantially equal to 100%. As used herein, the term “stepcoverage” is defined as percentage ratio of a thickness of the metaloxide film on a sidewall of the substrate 302 to the thickness of themetal oxide on a horizontal surface of the substrate 300.

As a non-limiting example of the cyclical deposition processes of thedisclosure FIG. 5 illustrates a field emission scanning electronmicroscope (FESEM) image of a semiconductor structure including a gapfeature with a conformal metal oxide disposed thereon. In more detail,FIG. 5 illustrates a semiconductor structure 500 including a siliconsubstrate 502 with a gap feature 504 comprising a trench having anaspect ratio of approximately 1:1. Disposed directly over the siliconsubstrate 502 and particularly directly over the gap feature 504 is anapproximately 40 nanometer thick conformal zinc oxide (ZnO) film 506deposited according to the embodiments of the disclosure.

Once a metal oxide film has been deposited to a desired thickness theexemplary gap fill process 100 (FIG. 1) may continue by means of aprocess block 130 comprising, contacting the metal oxide film with anorganic ligand vapor, and converting at least a portion of the metaloxide film to a porous material thereby filling the one or more gapfeatures.

In more detail, the embodiments of the disclosure may comprise asolid-vapor conversion process wherein the metal oxide is contacted withat least one organic ligand vapor thereby converting at least a portionof the metal oxide film to a porous material. In some embodiments of thedisclosure, contacting the metal oxide film with the organic ligandvapor may be performed in same reaction chamber utilized to perform thecyclical deposition process 120, whereas in alternative embodiments thesubstrate with the metal oxide film disposed thereon may be transferredto a second reaction chamber for subsequently contacting the metal oxidefilm with the organic ligand vapor. In embodiments wherein the substrateand the associated metal oxide film are transferred between a firstreaction chamber (configured for cyclical deposition) and a secondreaction (configured for contacting the metal oxide with the organicligand vapor), the first and second reaction chamber may be integratedon a common semiconductor processing apparatus comprising a cluster tooland the transfer between the first reaction chamber and the secondreaction chamber may be performed under a controlled environment toprevent unwanted contamination of the substrate and the metal oxidefilm.

Once the substrate and associated metal oxide film are disposed within asuitable reaction chamber the substrate may be heated to a desiredsubstrate temperature for the conversion of the metal oxide film to aporous material. For example, the substrate may heated to a temperatureof less than 500° C., or less than 300° C., or even than 200° C., orless than 160° C., or less than 140° C., or less than 120° C., or fromabout 0 to about 300° C., or from about 20 to about 250° C., or fromabout 50 to about 200° C., from about 70 to about 160° C., or from about80 to about 140° C. prior to or when contacting the metal oxide filmwith the organic ligand vapor.

In some embodiments of the disclosure, the organic ligand vapor maycomprise a carboxylic acid vapor. In some embodiments of the disclosure,the organic ligand vapor may comprise cyclic aromatic or aliphaticcompound. In some embodiments, the carboxylic acid vapor may comprise adicarboxylic acid vapor or a tricarboxylic acid vapor. In someembodiments, the carboxylic vapor may comprise carboxylic acid, forexample aliphatic carboxylic acid or aromatic carboxylic acid such as avapor of at least one of 1,4-benzenedicarboxylic acid,2,6-napthalenedicarobxylic acid, or 1,3,5-benezenetricarboxylic acid.

In some embodiments of the disclosure, the organic ligand vapor maycomprise a heterocyclic compound vapor comprising nitrogen, or sulphur,or oxygen or combinations thereof. In some embodiments, the heterocycliccompound vapor may comprise a five-membered ring heterocyclic compound.In some embodiments, the five membered ring heterocyclic compound maycomprise two heteroatoms, at least one heteroatom comprising a nitrogenatom. Therefore, in some embodiments of the disclosure, the organicligand vapor may comprise an azole vapor or an imidazole vapor,including, but not limited to, at least one of 2-methylimidazole,3-(2-Pyridyl)-5-(4-pyridyl-1,2,4-triazole), or 4,5-dichloroimidazole.

In some embodiments of the disclosure, contacting the metal oxide withan organic ligand vapor may comprise pulsing the organic ligand vaporinto the reaction chamber and subsequently contacting the substrate tothe organic ligand vapor for a time period of between about 0.1 secondsand about 3600 seconds, between about 0.5 seconds and about 1200seconds, or between about 1 seconds and about 600 seconds. In addition,during the pulsing of the organic ligand vapor into the reaction chamberand contacting the metal oxide with the organic ligand vapor, the flowrate of the organic ligand vapor may be less than 2000 sccm, or lessthan 1000 sccm, or even less than 250 sccm. The organic ligand vapor maybe heated in a source vessel in order to get enough vapor pressure fordelivery to the reaction chamber. In some embodiments of the disclosure,contacting the metal oxide with an organic ligand vapor may comprisealso continuous or pulsed flow or static atmosphere of air and/or inertgases, such as N2 and noble gases like, He and Ar.

The process block 130 of exemplary gap fill process 100 (FIG. 1) alsocomprises, converting at least a portion of the metal oxide film to aporous material thereby filing the one or more gap features. In someembodiments, contacting the metal oxide film with the organic ligandvapor and converting at least a portion of the metal oxide to the porousmaterial are performed simultaneously, the contacting of the metal oxidefilm with the organic ligand vapor producing the conversion of at leasta portion of the metal oxide film to the porous material. In otherwords: contacting the metal oxide film with the organic ligand vaporconverts at least a portion of the metal oxide film into a porousmaterial. In some embodiments of the disclosure, converting at least aportion of the metal oxide film comprises fully converting the metaloxide film to the porous material, i.e., the entire thickness of themetal oxide film is converted to the porous material.

In some embodiments of the disclosure, the metal oxide film has aninitial thickness and converting at least a portion of the metal oxidefilm to the porous material produces the porous material with athickness greater than the initial thickness of the metal oxide filmwithout additional deposition. The porous material may have a lowermolar density than the volumetric mass density of the metal oxide filmand therefore as the metal oxide film is converted to the porousmaterial an expansion of the film may take place, the expansionresulting in a porous material which fills the one or more gap featureswithout the need for additional deposition processes, as illustrated inFIG. 3C wherein the porous material 310 fills the one or more gapfeatures 304 disposed over or in substrate 302.

In some embodiments of the disclosure, the porous material may comprisea metal-organic framework (MOF) material wherein a MOF materialcomprises a metal component, such as, metal ions or clusters of metalions, coordinated to organic ligands. For simplicity reasons metaloxides deposited and then converted at least partially to MOF orconverted hybrid structures posing density less than the metal oxide areconsidered as MOF's herein in this disclosure. In some embodiments MOF'sare fully converted metal-oxide frameworks where as in other embodimentsMOF's can be only partially converted. In some embodiments, the metalcomponent of the MOF material may comprise at least one metal selectedfrom the group comprising zinc (Zn), zirconium (Zr), aluminum (Al),copper (Cu), or iron (Fe). In some embodiments, the MOF material doesnot comprise substantial amounts, for example, more than trace amountsof other metal than zinc (Zn), zirconium (Zr), aluminum (Al), copper(Cu), or iron (Fe). In some embodiments, the MOF material does notcomprise Zn. In some embodiments, the MOF material does comprise Al asonly metal. In some embodiments, the MOF material does comprise Zr asonly metal. In some embodiments, the MOF material may comprise ZIF-8. Insome embodiments, the MOF material may have a dielectric constant ofless than approximately 4.0, or less than 3.5, or less than 3.0, or lessthan 2.5, or less than 2.2, or less than 2.0, or less than 1.8, or lessthan 1.6, or less than 1.5, or even less than 1.4.

The embodiment of the disclosure may provide gap fill processes and gapfill materials which are superior to prior known methods. An example ofa semiconductor structure including a gap feature filled with adielectric material by common prior art methods is illustrated in FIG.6. For example, FIG. 6 illustrates a cross-sectional view of asemiconductor structure 600 comprising a substrate 602 (e.g., bulksilicon) comprising a gap feature 604, the gap feature 604 being filledwith a dielectric gap fill material 606 (e.g., silicon dioxide). Asillustrated in FIG. 6, disposed within the dielectric gap fill material604 is a feature commonly referred to as a seam 608. A seam refers to aregion in the dielectric gap fill material 606 where the edges of twofilms growing from both sidewalls of the gap feature touch each other,therefore the seam 608 is commonly disposed at the center of the gapfeature 604. The formation of a seam 608 in dielectric gap fill materialis undesirable and may result in poor device performance and subsequentissues in semiconductor device fabrication processes. The seam 608 maycomprise a vertical line or one or more macro-voids that may beobservable using scanning transmission electron microscopy (STEM) ortransmission electron microscopy (TEM) where, if observations reveal avertical line or one or more macro-voids in the dielectric gap fillmaterial 606, a seam 608 is present.

In contrast, the embodiments of the current disclosure form a porous gapfill material 310 in the one or more gap features 304 (FIG. 3C) whichhas no seam, i.e., the porous material 310 disposed in the one or moregap features 302 is seamless. In addition, in some embodiments theporous gap fill material 310 of the current disclosure maybe free ofmacro-voids commonly found in prior gap fill processes and structures,wherein macro-voids can be differentiated from the plurality of poresdisposed in the porous gap fill material as the plurality of pores inthe porous gap fill material may comprise micro- or nano-voids. Further,in the case of MOF material, pores can be part of the crystal structureof the gap fill material, whereas macro-voids may not be part of thecrystalline structure of the gap fill material. In some embodiments, theporous gap fill material 310 may have a pore size of 0.5 nm to 2.0 nm,more than 1.0 nm, more than 2.0 nm, more than 5.0 nm, more than 10 nm,more than 20 nm, more than 40 nm, or pore size from 1 to 100 nm, from 2to 50 nm, from 2 to 30 nm, or from 5 to 20 nm. Whereas macro-voids arelarger. In some embodiments, the porous gap fill material 310 may have asurface area of more than 100 m²/g, more than 500 m²/g, more than 1000m²/g, more than 2500 m²/g, more than 5000 m²/g, more than 7500 m²/g ormore than 10000 m²/g. In some embodiments, the porous gap fill material310 may have volumetric mass density below 2.0 g/cm³, below 1.5 g/cm³,below 1.5 g/cm³, below 1.0 g/cm³, below 0.7 g/cm³, below 0.5 g/cm³,below 0.4 g/cm³, below 0.3 g/cm³, below 0.2 g/cm³, below 0.15 g/cm³.

In addition, in some embodiments, the porous gap fill material 310 maycomprise a MOF material and the MOF material may be continuous andpin-hole free, wherein a pin-hole may refer to a cavity or hole thatextends through the thickness of the MOF material. In some embodiments,the MOF materials fills the gap, trench, via or other three-dimensionalfeature, such as reentrant structure, so that less than 30%, less than20%, less than 10% , less than 5%, less than 3%, less than 2%, less than1%, less than 0.5%, less than 0.1%, less than 0.05%, less than 0.01% ofvolume or cross-sectional area is not occupied with the MOF (i.e., seamvolume), for example when studied in cross-sectional imaging such ascross-sectional STEM or TEM. Internal inherent cavities of the MOFstructure are not counted as seam.

In some embodiments of the disclosure, the porous film 310 may comprisea MOF material and may be formed to a thickness of less than 300nanometers, or less than 100 nanometer, or less than 50 nanometer, orless than 20 nanometer, or less than 10 nanometer, or even less than 5nanometers.

The exemplary gap fill process 100 (FIG. 1) may continue by means of aprocess block 140 comprising a decision gate dependent on the thicknessof the porous material. If the porous material is formed to a desiredthickness thereby filling the one or more gap features then theexemplary gap fill process 100 may exit by means of a process block 150.In alternative embodiments, the porous material may be formed to athickness, which is insufficient to fill the one or more gap features,as may be the case when the one or more gap features are spaced widelyapart and have high aspect ratios, and the exemplary gap fill process100 may be repeated one or more times.

In more detail, the exemplary gap fill process 100 may comprise asuper-cycle 125, wherein the super-cycle may be repeated one or moretimes, a unit super-cycle 125 comprising: depositing a metal oxide filmby a cyclical deposition process and subsequently contacting the metaloxide with an organic ligand vapor and converting at least a portion ofthe metal oxide film to a porous material. The super-cycle 125 may beperformed one or more times until a porous material is formed to asufficient thickness to fill the one or more gap features.

FIGS. 4A-$E illustrate cross-sectional views of semiconductor structuresformed by the exemplary gap fill process 100 when utilizing more thanone super-cycle 125 of the exemplary gap fill process 100. For example,FIG. 4A illustrates a semiconductor structure 400 comprising a substrate402 comprising a gap feature 404 comprising a wide gap and high aspectratio, wherein d denotes the gap width and, and the aspect ratio may begreater than 1:1, greater than 2:1, greater than 4:1, greater than 8:1,greater than 20:1, greater than 40:1, greater than 80:1, greater than150:1 or greater than X:1, or even greater than X:1. In some embodimentsthe gap, trench, via or other three-dimensional feature, such asreentrant structure has width or opening at the top of the planarsurface of less than about 500 nm, less than about 100 nm, less thanabout 70 nm, less than about 50 nm, less than about 30 nm, less thanabout 20 nm, less than about 10 nm, less than about 7 nm, less thanabout 5 nm, or even less than about 4 nm, and depth of more than about 5nm, more than about 10 nm, more than about 20 nm, more than about 40 nm,more than about 80 nm, more than about 200 nm, more than about 500 nm,or even more than about 1000 nm. In some embodiments the wafer havinggap, trench, via or other three-dimensional feature like reentrantstructure, such as 300 mm patterned silicon wafer, has surface area ofmore than 5, more than 10, more than 25, more than 50, more than 100,more than 200 times compared to blanket wafer. FIG. 4B illustrates asemiconductor structure 405 comprising, the substrate 402 with aconformal metal oxide film 406, e.g., a zinc oxide film, formed thereonby a cyclical deposition process 120 (FIGS. 1 and 2).

FIG. 4C illustrates a semiconductor structure 415 comprising, thesubstrate 402 and a porous material 410 formed by means of process block130 (FIG. 1), i.e., by contacting the metal oxide with an organic ligandand converting at least a portion of the metal oxide film to a porousmaterial. In this non-limiting example, the entire thickness of themetal oxide film is converted to the porous material, however theexpansion and associated increase in film thickness resulting from theconversion of the metal oxide film to the porous material isinsufficient to fill the gap feature 404.

Therefore, in some embodiments of the disclosure, the super-cycle 125(FIG. 1) of exemplary gap fill process 100 may be repeated in order tocompletely fill the gap feature. The exemplary gap fill process 100 maytherefore return to the process block 120 and an additional metal oxidefilm may be deposition by cyclical deposition process 120. For example,FIG. 4D illustrates a semiconductor structure 420 comprising, substrate402 with the porous material 410 disposed thereon, and an additionalmetal oxide film 422 disposed over the porous material 410.

Upon cyclical deposition of the additional metal oxide film, theexemplary gap fill process may continue by means of the process block130 comprising, contacting the additional metal oxide film with anorganic ligand vapor and converting at least a portion of the additionalmetal oxide to a porous material. For example, FIG. 4E illustrates asemiconductor structure 425 comprising, the substrate 402, the porousmaterial 410, and an additional porous material 426, wherein theadditional porous material 426 fills the gap feature. Upon filling theone or more gap features with a porous material, i.e., forming a porousmaterial to the desired thickness, the exemplary gap fill process 100(FIG. 1) may exit via the process block 150 and the substrate with theporous material disposed thereon may be subjected to furthersemiconductor fabrication processes to produce a desired semiconductordevice structure.

As a non-limiting example of the embodiments of the disclosure, FIG. 7illustrates a scanning transmission electron microscope (STEM) image ofa semiconductor structure including a number of gap features filled witha porous material formed according to the embodiments of the disclosure.In more detail, the semiconductor structure 700 comprises a siliconsubstrate 702 including a number of gap features 704 with an aspectratio of approximately 1:1. A conformal zinc oxide film with a thicknessof approximately 6 nanometers was cyclically deposited directly over thesilicon substrate 702 and the zinc oxide film was subsequent contactedwith 2-methylimidazle to convert the zinc oxide film to the porousmaterial 710 which fills the gap features 704. In this non-limitingexample, the porous material comprises a metal-organic frameworkmaterial referred to as ZIF-8. The confirmation of the completeconversion of the zinc oxide film to ZIF-8 is corroborated by FIG. 8which illustrates an x-ray diffraction (XRD) measurement taken from theporous gap fill material 710 which has a crystalline structure thatmatches that of ZIF-8 and does not indicate the presence of anyremaining zinc oxide.

The embodiments of the disclosure may also disclose semiconductorstructures and particular semiconductor structures including ametal-organic framework material. Therefore the embodiments of thedisclosure may comprise a semiconductor structure comprising: asubstrate comprising a non-planar surface including one or more gapfeatures; and a metal-organic framework material disposed in and fillingthe one or more gap features.

In more detail, FIG. 3C illustrates a semiconductor structure 308 whichcomprises a substrate 3002 with one or more gap features 304 disposedthereon, or therein, and a metal-organic framework material 310 which isdisposed in the one or more gap features 304 and fills the one or moregap features 304. In some embodiments of the disclosure, the one or moregap features 304 may have a maximum aspect ratio of greater than 2:1. Insome embodiments of the disclosure, the one or more gap features mayhave a minimum aspect ratio of less than 5:1.

In some embodiments of the disclosure, the metal-organic frameworkmaterial 310 may comprise ZIF-8. In some embodiments, the metal-organicframework material 310 is continuous and pin-hole free. In someembodiments, the metal-organic framework material 310 is seamless, i.e.,free of one or more macro-voids. In some embodiments, the metalorganicframework material 310 may have a dielectric constant of less than 4.0,or less than 3.5, or less than 3.0, or less than 2.5, or less than 2.2,or less than 2.0, or less than 1.8, or less than 1.6, or less than 1.5,or even less than 1.4. In some embodiments, the metalorganic frameworkmaterial 310 may have a pore size of 0.5 nm to 2.0 nm, more than 1.0 nm,more than 2.0 nm, more than 5.0 nm, more than 10 nm, more than 20 nm,more than 40 nm, or pore size from 1 to 100 nm, from 2 to 50 nm, from 2to 30 nm, or from 5 to 20 nm. In some embodiments, the metalorganicframework material 310 may have a surface area of more than 100 m²/g,more than 500 m²/g, more than 1000 m²/g, more than 2500 m²/g, more than5000 m²/g, more than 7500 m²/g or more than 10000 m²/g. In someembodiments, the metalorganic framework material 310 may have volumetricmass density below 2.0 g/cm³, below 1.5 g/cm³, below 1.5 g/cm³, below1.0 g/cm³, below 0.7 g/cm³, below 0.5 g/cm³, below 0.4 g/cm³, below 0.3g/cm³, below 0.2 g/cm³, below 0.15 g/cm³.

The example embodiments of the disclosure described above do not limitthe scope of the invention, since these embodiments are merely examplesof the embodiments of the invention, which is defined by the appendedclaims and their legal equivalents. Any equivalent embodiments areintended to be within the scope of this invention. Indeed, variousmodifications of the disclosure, in addition to those shown anddescribed herein, such as alternative useful combination of the elementsdescribed, may become apparent to those skilled in the art from thedescription. Such modifications and embodiments are also intended tofall within the scope of the appended claims.

What is claimed is:
 1. A method for filling a gap feature on a substratesurface, the method comprising: providing a substrate comprising anon-planar surface including one or more gap features; depositing a Zror Al oxide film over a surface of the one or more gap features by acyclical deposition process; contacting the metal oxide film with anorganic ligand vapor; and converting at least a portion of the metaloxide film to a porous material thereby filling the one or more gapfeatures.
 2. The method of claim 1, wherein contacting the metal oxidefilm with the organic ligand vapor and converting at least a portion ofthe metal oxide to the porous material are performed simultaneously, thecontacting of the metal oxide film with the organic ligand vaporproducing the conversion of at least a portion of the metal oxide filmto the porous material.
 3. The method of claim 1, wherein the one ormore gap features have a maximum aspect ratio of greater than 2:1. 4.The method of claim 1, wherein the one or more gap features have aminimum aspect ratio of less than 5:1.
 5. The method of claim 1, whereindepositing the metal oxide film further comprises depositing a conformalmetal oxide film with a step coverage greater than 90%.
 6. The method ofclaim, 1 wherein the cyclical deposition process comprises at least oneunit cycle, one unit cycle comprising: contacting the substrate with ametal vapor phase precursor; and contacting the substrate with anoxidizing precursor.
 7. The method of claim 6, wherein the metal vaporphase precursor comprises a metal selected from the group comprisingzirconium (Zr) or aluminum (Al), and wherein the oxidizing precursorcomprises at least one of water (H₂O), hydrogen peroxide (H₂O₂), ozone(O₃), an organic alcohol, or an oxygen based plasma.
 8. The method ofclaim 1, wherein the metal oxide comprises a zinc oxide.
 9. The methodof claim 1, wherein the metal oxide film is deposited to a thickness ofless than 20 nanometers.
 10. The method of claim 1, wherein the organicligand vapor comprises a carboxylic acid vapor.
 11. The method of claim10, wherein the carboxylic acid vapor comprises a vapor of at least oneof 1,4-benzenedicarboxylic acid, 2,6-napthalenedicarobxylic acid, or1,3,5-benezenetricarboxylic acid.
 12. The method of claim 1, wherein theorganic ligand vapor comprises an azole vapor.
 13. The method of claim12, wherein the azole vapor comprises a vapor of at least one of2-methylimidazole, 3-(2-Pyridyl)-5-(4-pyridyl-1,2,4-triazole), or4,5-dichloroimidazole.
 14. The method of claim 1, wherein the porousmaterial comprises a metal-organic framework material.
 15. The method ofclaim 14, wherein the metal-organic framework material has a dielectricconstant of less than approximately 4.0.
 16. The method of claim 14,wherein the metal-organic framework material is continuous and pin-holefree.
 17. The method of claim 14, wherein the metal-organic frameworkmaterial has a thickness of less than 50 nanometers.
 18. The method ofclaim 1, wherein the porous materials fills the one or more gap featureswithout the formation of a seam.
 19. The method of claim 1, whereinconverting at least a portion of the metal oxide film comprises fullyconverting the metal oxide film to the porous material.
 20. The methodof claim 1, further comprising repeating the steps of depositing themetal oxide film and contacting the metal oxide with the organic ligandvapor one or more times.
 21. The method of claim 1, wherein the metaloxide film has an initial thickness and converting at least a portion ofthe metal oxide film to the porous material produces the porous materialwith a thickness greater than the initial thickness without additionaldeposition.